Ciao a tutti and so far my Italiano . I'm conducting an international survey to find out about suitable O-ring and/or X-ring drivechains for CB500s and CB550s if there are any. Among owners of CB500s and CB550s there's much concern about those chains eating into the crankcase. I have heard several stories and would like to find out what is true and if there are any of these chains that will NOT rub into the case. If you have experience - positive or negative - please let us know. Grazie!